Tire with sidewall carcass reinforcement

ABSTRACT

A tire having at least one crescent-shaped rubber composition as an insert in its sidewall region which is comprised of at least one diene-based elastomer, carbon black and, optionally, silica and at least one of dithiodipropionic acid, benzoic acid and salicylic acid.

FIELD

[0001] This invention relates to a tire and more particularly to apneumatic tire designed for optional use without internal air pressure.

BACKGROUND

[0002] Tire constructions have been suggested for pneumatic tires whichare designed to be run without internal pneumatic pressure, other thanambient atmospheric pressure.

[0003] For example, tires have been suggested which have specialsidewall inserts designed to improve sidewall stiffness, therebyreducing, or inhibiting, the tire's tendency to go flat without internalair pressure. (see, for example, U.S. Pat. No. 5,368,082). Also, tireshave been suggested which have additional plies, such as tires having atotal of three plies in their sidewalls, to enhance, or substantiallymaintain, the tire's performance when running without internal airpressure. (see, for example, U.S. Pat. Nos. 5,427,166 and 5,511,599).

[0004] For this invention, it is desired to provide a tire with insertsin its sidewall portion(s) which have enhanced stiffness relatedproperties.

[0005] In the description of this invention, the term “phr” where used,relates to parts by weight of specified material, or ingredient, per 100parts by weight rubber, in a rubber based composition. Such term is wellknown to those having skill in such art.

[0006] Such terms as “compound” or “rubber compound” or “rubbercomposition” are used interchangeably. The term “compounding ingredient”refers to ingredients, usually including the elastomers themselves, thatare blended to form a rubber compound. Such terms are well known tothose having skill in such art.

[0007] In the description of this invention, the viscoelastic propertiesE′ and Tangent (Tan.) delta values art determined by a Rheovibroninstrument at 11 hz at a one tenth percent strain. A Rheovibroninstrument from the Tmass company is used. It is understood that use ofa Rheovibron instrument and such method of measurement of E′ andTan.Delta is understood by one having skill in the art. The E′ andTan.Delta values are to be determined at 60° C.

[0008] The term “runflat” tire, where used, relates to a pneumatic tirewhich is designed to run without internal air pressure, under ambientconditions, for limited periods of time and speeds.

SUMMARY AND PRACTICE OF THE INVENTION

[0009] In accordance with this invention, a tire is provided comprisedof a toroidally-shaped carcass and an outer, circumferential treaddesigned to be ground-contacting, wherein said carcass is comprised oftwo spaced apart inextensible bead portions, two spaced apart sidewallseach individually extending radially inward from and connecting saidtread to said bead potions, and at least one cord reinforced plyextending from bead to bead and through the sidewalls; an improvement inwhich a substantially crescent shaped rubber insert is juxtapositionedto and axially inward of at least one of said carcass plies in each ofsaid sidewalls or the tire; wherein the rubber composition of saidinsert has a Shore A hardness at 100° C. in a range of about 65 to about85, a 100 percent Modulus in a range of about 3.5 to about 10 MPa, a HotRebound at 100° C. in a range of about 60 to about 80, an E′ value in arange of about 2 to about 20 MPa at 60° C. and a Tan.Delta value at 60°C. in a range of about 0.03 to about 0.15; and wherein said rubbercomposition of said insert is comprised of, based on 100 parts by weightrubber, (A) at least one diene-based elastomer, (B) about 30 to about100 phr of particulate reinforcement as carbon black and, optionally,silica, and (C) about 0.5 to about 10 phr of at least one ofdithiodipropionic acid, benzoic acid and salicylic acid.

[0010] Preferably, the material (C) is 3,3′ dithiodipropionic acid,although it is understood that it may exist in a 2,2′ isomeric form.

[0011] It is to be appreciated that the insert is sulfur co-cured withthe tire assembly of said tread and carcass as a whole.

[0012] Preferably, the insert(s) have a maximum thickness at a locationabout midway between the bead portions and the tread in the sidewallregion of the tire.

[0013] In one aspect of the invention, said dithiodipropionic acid,benzoic acid and/or salicylic acid are added by either (i) addingin-situ with ingredients for the said rubber composition or (ii) withthe rubber composition as a composite of carbon black and/or silicapre-treated with at least one of said acids such as, for example, byorganic solvent deposition or melt dispersion methods. For example, atleast one of said acids may be adsorbed, absorbed, coated or melted,such as, for example, melt-spraying of molten material, onto the surfaceof said carbon black and/or silica filler.

[0014] By blending one or more of said acids, preferably thedithiodipropionic acid, in-situ with ingredients of the rubbercomposition, it is meant that it is added to and mixed with the rubbercomposition as an individual ingredient.

[0015] By pre-blending one or more of such acids, preferably thedithiodipropionic acid, with at least a portion of the carbon blackand/or silica it is meant that it is pre mixed with the carbon blackand/or silica prior to form a composite thereof and such composite isadded to and mixed with ingredients for the rubber composition as anindividual ingredient.

[0016] By mixing with ingredients for the rubber composition, it ismeant that one or more of the said acids, or said composite, as the casemay be, is blended with the elastomer(s) as well as conventionalcompounding ingredients used for the rubber composition for the insert,conventionally in an internal rubber mixer. It is preferred the saidacid, preferably the dithiodipropionic acid, or said composite, as thecase may be, is mixed with the compounding ingredients in the absence ofcuratives such as sulfur and vulcanization accelerators, and that suchcuratives are subsequently blended with the rubber composition aftersaid acid or composite addition.

[0017] Alternatively, although not generally preferred, a portion of orall of the acid, or composite, may be added to the rubber compositionwith the curatives.

[0018] The dithiodipropionic acid may typically be characterized byhaving a melting point in the range of about 153 to about 159° C. Suchmelting point can conveniently be determined by a differential scanningcalorimeter (DSC) at a heating rate of 10° C. per minute.

[0019] It is considered herein that the utilization of the said acids,particularly the 3,3′-dithiodipropionic acid, for the rubber fillercomposition is significant in order to enhance the stiffness of thesulfur vulcanized rubber composition of the insert as well as toendeavor to substantially maintain a relatively low hysteresis.

[0020] In the practice of this invention, a significant function of therubber composition based fillers in the sidewall portion of the tire isto stiffen/support the sidewall structure when the tire is operatedwithout inflation pressure.

[0021] The rubber composition based inserts are elastomeric in naturehaving a substantially crescent cross-sectional shape and materialproperties selected to enhance inflated ride performance while promotingthe tire's run-flat durability. The inserts, if desired, may also beindividually reinforced with cords or short fibers. Thus, one or more ofsuch inserts may be so-reinforced.

[0022] The shape of the fillers is described as being substantiallycrescent in shape. This is intended to also include an entrunkatedcrescent shape, particularly where the entrunkated portion of thecrescent shaped filler is juxtapositioned to the tire's bead portion.

[0023] In further practice of the invention, said tire carcass may havefrom one to three plies comprised of a first axially inner ply andoptionally one or two additional plies as a second ply and third ply,respectively, each additional ply positioned sequentially axiallyoutward from said first ply in the sidewall region of the tire.

[0024] Accordingly, in accordance with this invention said tire containsone ply in its carcass wherein said insert is juxtapositioned to andaxially inward of said ply in the sidewall region of the tire.

[0025] In further accordance with this invention, said tire contains, inits carcass, an axially inner first ply and a second ply axially outwardfrom the first ply; wherein said insert is juxtapositioned to andaxially inward of said first ply, in the sidewall region of the tire.

[0026] In additional accordance with this invention, said tire contains,in its carcass, an axially inner first ply and an axially outer secondply; wherein said insert is juxtapositioned to and interposed betweensaid first and second ply, in the sidewall region of the tire.

[0027] In further accordance with this invention, said tire contains, inits carcass, an axially inner first ply and an axially outer second ply;wherein one of said inserts is juxtapositioned to and interposed betweensaid first and second ply, in the sidewall region of the tire, andanother of said inserts is juxtapositioned to and axially inward of saidfirst ply, in the sidewall region of the tire.

[0028] In further accordance with this invention, said tire contains, inits carcass, an axially inner first ply, a second ply axially outwardfrom said first ply and a third ply axially outward from said secondply; wherein said insert is juxtapositioned to and axially inward ofsaid first ply, in the sidewall region of the tire.

[0029] In additional accordance with this invention, said tire contains,in its carcass, an axially inner first ply, a second ply axially outwardfrom said first ply and a third ply axially outward from said secondply; wherein said insert is juxtapositioned to and interposed between(a) said first and second plies and/or (b) said second and third plies,in the sidewall region of the tire.

[0030] In further accordance with this invention, said tire contains, inits carcass, an axially inner first ply, a second ply axially outwardfrom said first ply and a third ply axially outward from said secondply; wherein said insert is juxtapositioned to and interposed between(a) said first and second plies and/or (b) said second and third plies,in the sidewall region of the tire and, also, an insert juxtapositionedto and axially inward of the innermost of said plies.

[0031] In one embodiment, the innermost ply, or plies, has synthetic ortextile cord reinforcement of polyester, nylon, rayon or aramid,preferably nylon; while the outermost ply preferably has aramid, carbonfiber, fiberglass or metal cord reinforcement, preferably brass and/orzinc coated steel cords.

[0032] Thus, in a preferred embodiment, the first ply has reinforcingcords of nylon, an aramid fiber, and the second and additional plies aresteel cords.

[0033] The term “ply” is contemplated to include cord reinforced insertswhich do not extend entirely from one bead core to the opposite beadcore. It is, however, contemplated that at least one ply must extendfrom bead core to the opposite bead core, preferably a radial ply. Asecond ply can extend from a bead core to just laterally under one ormore of the reinforcing belts of the belt structure.

[0034] In one aspect, the outermost ply preferably has cords of a highermodulus (i.e.: steel cords) and the innermost ply, or plies, have cordsof a lower modulus (i.e.: nylon or rayon).

[0035] At least one ply, preferably the innermost ply, extended frombead core to bead cord and wraps around the bead core. Alternatively,where two or more plies are used, at least one of the additional plies,while extending from bead core to bead core, does not actually wraparound the bead core.

BRIEF DESCRIPTION OF THE DRAWINGS

[0036]FIG. 1 is a fragmentary cross-sectional view of a tire showing itstread and carcass with one ply and one insert axially inward of the plyin the sidewall region of the tire as an embodiment of the invention.

[0037]FIG. 2 is a fragmentary cross-sectional view of tire showing itstread and carcass with two plies, a second insert interposed between theplies and a second ply axially outward of the innermost ply in thesidewall region of the tire as an embodiment of the invention.

[0038]FIG. 3 is a fragmentary cross-sectional view of a tire showing itstread and carcass with three plies, inserts between the plies andanother insert axially inward of the innermost ply in the sidewallregion of the tire as an embodiment of the invention.

DEFINITIONS

[0039] “Axial” and “axially”, where used, means directions that areparallel to the axis of rotation of the tire.

[0040] “Bead portion” means generally that part of the tire comprisingan annular inextensible tensile member such as a multiplicity of annularwires surrounded by an elastomer composition(s), and is associated withholding the tire to the rim being wrapped by ply cords and shaped, withor without other reinforcement elements such as flippers, chippers,apexes or fillers, toe guards and chaffers. The bead core usually refersto the wire beads of the bead portion but sometimes may refer to thebead portion itself.

[0041] “Belt Structure” or “Reinforcing Belts”, where used, means atleast two annular layers or plies of parallel cords, woven or unwoven,underlying the tread, unanchored to the bead, and having both left andright cord angles in the range from 17° to 27° with respect to theequatorial plane of the tire.

[0042] “Circumferential” may be used in the description to relate to adirection extending along (around) the outer perimeter of the surface ofthe tire carcass such as, for example, the circumferential tread on thecarcass.

[0043] “Carcass” means the tire structure apart from the tread butincluding supporting plies, sidewalls and the beads or bead portions.

[0044] “Chafers”, where used herein, refers to narrow strips of materialplaced around the outside of the bead to protect cord plies from therim, distribute flexing above the rim.

[0045] “Cord” means one of the reinforcement strands of which the pliesin the tire are comprised.

[0046] “Innerliner”, where used herein, means the layer or layers ofelastomer or other material that form the inside surface of a tubelesstire and that contain the inflating fluid within the tire.

[0047] “Ply” means a layer of rubber-coated parallel cords.

[0048] “Radial” and “radially” mean directions radially toward or awayfrom the axis of rotation of the tire.

[0049] “Radial Ply Tire”, if used herein, means a belted orcircumferentially-restricted pneumatic tire in which at least one plyhas cords which extend from bead to bead are laid at cord angles between65° and 90° with respect to the equatorial plane of the tire.

[0050] “Shoulder”, if used herein, means the upper portion of sidewalljust below the tread edge.

[0051] “Sidewall” means that portion of a tire between the tread and thebead.

DETAILED DESCRIPTION

[0052] Referring to the drawings FIGS. 1, 2 and 3 show the fragmentarycross-section of a tire (1), its tread (2), bead portion (3), sidewallor sidewall region (4), inextensible wire bead core (5), rubber chafer(6), rubber toeguard (7), rubber composition innerliner (8), beltstructure (9) underlying a portion of the tread (2), carcass ply (10),carcass ply turn-up (11), insert (12) and apex (13).

[0053] The cords for use in the carcass plies may comprise from one(monofilament) to multiple twisted filaments. The number of totalfilaments in the cord may range from 1 to 13.

[0054] The cords, particularly metallic cords, of the carcass ply aregenerally oriented such that the tire according to the present inventionis what is commonly referred to as a radial.

[0055] The steel cord of the carcass ply intersect the equatorial plane(EP) of the tire at an angle in the range of from 75° to 105°.Preferably, the steel cords intersect at an angle of from 82° to 98°. Amore preferred range is from 89° to 91°.

[0056] The first and second reinforcing ply structure each may comprisea single ply layer, however, any number of carcass plies may be used.

[0057] As further illustrated in the Figures, the first ply structurehas a pair of turn-up ends respectively which wrap about each bead core5 of the bead portion 3 of the carcass. The ends 11 of the second ply 10are in proximity to the bead core 5 and terminate radially adjacent oneither side of the bead core 5, above the bead core 5 or can be wrappedaround the bead core 5 and terminates radially below the turn-up end 11of the first ply 10 as shown. The turn-up ends 11 of the first ply 10wrap about the second ply ends and the bead core 5. The turn-up ends ofthe first ply 11 terminates radially a distance above the nominal rimdiameter of the tire 1 in proximity to the radial location of themaximum section width of the tire. In a preferred embodiment, theturn-up ends are located within 20% of the section height of the tirefrom the radial location of the maximum section width, most preferablyterminating at the radial location of the maximum section width.

[0058] The bead core 5 is preferably constructed of a single ormonofilament steel wire continuously wrapped.

[0059] Located within the bead region 3 and the radially inner portionsof the sidewall portions 4 are high modulus elastomeric apex insertsdisposed between carcass reinforcing structure 11 and the turn-up ends11, respectively. The elastomeric apex inserts 13 extend from theradially outer portion of bead portions respectively, up into thesidewall portion gradually decreasing in cross-sectional width. Theelastomeric apex inserts 13 terminate at a radially outer end.

[0060] The inserts 12 may extend from each bead region radially to theedge of the tread, usually to just beneath the reinforcing beltstructures 9. As illustrated in the Figures, the sidewall portions mayeach include a first insert 12 and a second insert 12 and even a thirdinsert 12. The first inserts 12 are positioned as described above. Thesecond inserts 12 are located (interposed) between the first and thesecond plies 10 respectively. The second insert 12 extends from eachbead region 3, or portion, radially outward to the edge of the tread 2,namely to just beneath the reinforcing belt structure 9.

[0061] In one embodiment, the first inserts 10 each have a thickness atits maximum thickness of at least three percent of the maximum sectionheight “SH” at a location approximately radially aligned the maximumsection width of the tire.

[0062] The second insert, and third insert, if used, has a thickness atits maximum thickness of at least one and one-half percent (1.5%) of themaximum section height of the tire at the location radially above themaximum section width of the tire. In a preferred embodiment theelastomeric second inserts, and third insert, if used, each have athickness of approximately one and one-half percent (1.5%) of themaximum section height SH of the tire at a radial location of about 75%of the section height SH. For example, in a P275/40ZR17 size highperformance tire this thickness of the second insert of the tire equals0.08 inches (2 mm). At the location approximately radially aligned withthe location of the maximum section width of the tire, the thickness ofthe second insert is 0.05 inches (1.3 mm).

[0063] The overall cross-sectional thickness of the combination ofelastomeric inserts preceding from the bead portions to the radiallocation of the maximum section width (SW) is preferably of constantthickness. The overall sidewall and carcass thickness is at least 0.45inches (11.5 mm) at the maximum section width location and increases toan overall thickness in the region where it merges into the shouldernear the lateral tread edges. Preferably, the overall thickness of thesidewall in the shoulder region of the tire is at least one hundredpercent (100%) of the overall sidewall thickness at the maximum sectionwidth (SW). This ratio means that the sidewall can be made substantiallythinner than the predecessor type runflat tires.

[0064] As previously discussed, the tire of the present invention has atleast one ply having a turn-up end 11 (wrapped around the bead core 5)while another ply can simply be terminated adjacent to the bead core 5without actually wrapping around the bead core 5.

[0065] The first insert 12 is preferably made of elastomeric material.The first insert 12 is designed to prevent the tire's sidewall fromcollapsing when operating under no inflation pressure. The insert 12 canbe of a wide range of shore A hardnesses from a relative soft shore A ofabout 50 to very hard 85, the material shape and cross-sectional profileis modified accordingly to insure the ride performance and sidewallspring rate is acceptable. The stiffer the material the thinner thecross-section generally.

[0066] The second insert 12, and third insert 12, if used, can be of thesame or different material physical properties relative to the firstinsert. This means that the combination of a hard second insert 12,and/or third insert 12 if used, with a softer first insert 12 iscontemplated as well as the combination of a hard first insert 12 with asofter second and/or third insert 12. The elastomeric materials of thesecond insert may similarly be in the 50 to 85 shore A range.

[0067] The second insert 12 and third insert 12, if used, as shown inthe Figures, is made of elastomeric material. These inserts 12 can beused in multiples of inserts interposed between adjacent plies when morethan two plies are used in the carcass structure.

[0068] The second inserts 12, and third inserts 12, when used, whenunreinforced with fibers, act as a spacer between the adjacent plies.The cords of the plies particularly the radially outer ply is placed intension when the tire is operated uninflated.

[0069] In practice, the rubber compositions for the inserts 12 utilizedin this invention for the aforesaid pneumatic tire construction arepreferably characterized by physical properties which enhance theirutilization in the invention which are, collectively, believed to be adeparture from properties of rubber compositions normally used inpneumatic tire sidewalls, particularly the combination of inserts 12 andwith plies 10 having a combination of either dissimilar or similar highstiffness yet essentially low hysteresis properties.

[0070] In particular, for the purposes of this invention, the aforesaidinserts 12 are designed to have a high degree of stiffness yet alsohaving a relatively low hysteresis for such a degree of stiffness. Thisenabled the benefits of the change in moduli of the reinforcing cords tobe fully appreciated.

[0071] The stiffness of the rubber composition for inserts 12 isdesirable for stiffness and dimensional stability of the tire sidewall4.

[0072] A similar stiffness of the rubber composition for the ply coatfor one or more of plies is desirable for overall dimensional stabilityof the tire carcass, including its sidewalls, since it extends throughboth sidewalls and across the crown portion of the tire.

[0073] However, it is to be appreciated that rubbers with a high degreeof stiffness in pneumatic tires normally be expected to generateexcessive internal heat during service conditions (operating as tires ona vehicle running under load and/or without internal inflationpressure), particularly when the rubber's stiffness is achieved by arather conventional method of simply increasing its carbon blackcontent. Such internal heat generation within the rubber compositiontypically results in a temperature increase of the stiff rubber andassociated tire structures which can potentially be detrimental to theuseful life of the tire 1.

[0074] The hysteresis of the rubber composition is a measure of itstendency to generate internal heat under service conditions. Relativelyspeaking, a rubber with a lower hysteresis property generates lessinternal heat under service conditions than an otherwise comparablerubber composition with a substantially higher hysteresis. Thus, in oneaspect, a relatively low hysteresis is desired for the rubbercomposition for the fillers and the plycoat(s) for one or more of theplies 10.

[0075] Hysteresis is a term for heat energy expended in a material(e.g.: cured rubber composition) by applied work and low hysteresis of arubber composition is indicated by a relatively high rebound andrelatively low tangent delta (Tan. Delta) property values.

[0076] Accordingly, it is important that the rubber compositions for oneor more of the inserts 12 and plycoats for one or more of plies 10 havethe properties of both relatively high stiffness and low hysteresis.

[0077] The following selected desirable properties of the rubbercompositions for the inserts 12 are summarized in the following Table A.TABLE A Properties Filler Hardness 100° C. (Shore A)¹ 65-85 Modulus(100%) MPa² 3.5-10  Hot Rebound (100° C.)³ 60-80 E′ at 60° C. (MPa)⁴ 2-20 Tan.Delta 60° C.⁴ 0.03-0.15

[0078] Alternatively, where two or more inserts are used, the firstinsert may have properties the same as or different from the second orthird inserts, if used, within the above stated ranges.

[0079] For example, the innermost insert may have a Shore A hardness ina range of about 65 to about 75, a 100 percent modulus in a range ofabout 3.5 to about 8 MPa, and E′ in a range of about 2 to about 15 MPaat 60° C. and a Tan.Delta at 60° C. in a range of about 0.03 to about0.1 and said outward insert(s) may have a Shore A hardness in a range ofabout 70 to about 85, a 100 percent modulus in a range of about 5 toabout 10 MPa, and E′ in a range of about 5 to about 20 MPa at 60° C. anda Tan Delta at 60° C. in a range of about 0.05 to about 0.15.

[0080] The indicated hardness property is considered to be an expandedrange of moderate rubber hardness permitted by the use of the unique plycord structure.

[0081] The indicated modulus property at 100% modulus is utilizedinstead of a 300% modulus because the cured rubber has a relatively lowultimate elongation at its breaking point. Such a cured rubber isconsidered stiff.

[0082] The indicated E′ property is a coefficient of the storage orelastic moduli component of the viscoelastic property which is anindication of the material (e.g.: cured rubber composition) stiffnesswhere a higher E′ value indicates a higher stiffness.

[0083] The indicated Tan. Delta property is a measure of the rubbercomposition's heat build up which is an indication of the hystereticnature of the material (e.g.: cured rubber composition) with arelatively low Tan Delta value at 100° C. being indicative of arelatively low hysteresis and a relatively low heat build up quality.

[0084] The utilization of both the E′ and Tan.Delta properties tocharacterize stiffness and hysteresis of rubber compositions is wellknown to those having skill in such characterizations of rubber.

[0085] The indicated hot rebound test property at about 100° C. ismeasured by Zwick Rebound Test (DIN 53512) test and is indicative of thematerial's (e.g.: cured rubber composition) resilience.

[0086] Thus, the properties illustrated in the previous Table A indicatea cured rubber composition with a relatively high stiffness, moderatehardness and a relatively low hysteresis for a rubber with such a highstiffness.

[0087] The low hysteresis is demonstrated by the relatively lowTan.Delta, and high rebound properties and is considered necessary for arubber composition desired to have a relatively low internal heatbuildup in service.

[0088] In the compounding of the various tire components, variousrubbers may be used which are, preferably, relatively high unsaturationdiene-based rubbers. Representative examples of such rubbers are,although they may not be so limited, are: styrene-butadiene rubber,natural rubber, cis 1,4 and trans 1,4-polyisoprene rubbers, cis 1,4,vinyl 1,2-and trans 1,4-polybutadiene rubbers,styrene-isoprene-butadiene rubber, styrene-isoprene rubber andisoprene-butadiene rubber.

[0089] Various of the preferred rubbers for the rubber compositions forthe fillers and for the plycoat(s) for one or more of the plies arenatural cis 1,4-polyisoprene rubber, isoprene/butadiene rubber, and cis1,4-polybutadiene rubber.

[0090] Preferred combinations, or blends, of rubbers are natural andsynthetic cis 1,4-polyisoprene rubber and cis 1,4-polybutadiene rubberfor the fillers and natural cis 1,4-polyisoprene rubber, cis1,4-polybutadiene rubber and isoprene/butadiene copolymer rubber for theplycoat(s).

[0091] In a preferred practice, based on 100 parts by weight rubber, (A)the fillers are comprised of about 60 to 100, preferably about 60 to 90,parts natural rubber and, correspondingly, up to about 40, preferablyabout 40 to about 10, parts of at least one of cis 1,4 polybutadienerubber and isoprene/butadiene rubber preferably cis 1,4-polybutadienerubber, where said isoprene/butadiene rubber, if used, is present in amaximum of 20 parts, and (B) the said plycoat(s) are comprised of up to100, preferably about 80 to about 100 and more preferably about 80 toabout 95, parts natural rubber and, correspondingly, up to about 100,preferably up to about 20 and more preferably about 20 to about 5, partsof at least one of isoprene/butadiene copolymer rubber and cis 1,4polybutadiene rubber, preferably an isoprene/butadiene rubber; whereinthe ratio of isoprene to butadiene in said isoprene/butadiene copolymerrubber is in a range of about 20/80 to about 80/20.

[0092] It is further contemplated, and is considered to be within theintent and scope of this invention that a small amount, such as about 5to about 15 parts, of one or more organic solution polymerizationprepared rubbers may be included with the aforesaid natural rubber, andcis 1,4-polybutadiene rubber and/or isoprene/butadiene rubbercomposition(s) for the said fillers and/or plycoat(s), of which theoption and selection of such additional rubber(s) can be made by onehaving skill in the rubber compounding art without undueexperimentation.

[0093] Thus, in such circumstance, the description of the filler andplycoat rubbers is set forth in a “comprising” manner with the intentthat small amounts of such solution polymerization prepared elastomerscan be added so long as the aforesaid physical property parameters ofthe cured rubber compositions are met. It is considered that such rubbercompounding is within the skill of those with experience in the rubbercompounding art without undue experimentation.

[0094] While not necessarily limited thereto, such other contemplatedsolution prepared rubbers are styrene/butadiene, and polymers of one ormore of isoprene and butadiene such as trans 1,4-polyisoprene, trans1,4-polybutadiene, styrene/isoprene/butadiene terpolymers and mediumvinyl polybutadiene.

[0095] It should readily be understood by one having skill in the artthat rubber compositions for components of the pneumatic tire, includingthe first and second fillers can be compounded by methods generallyknown in the rubber compounding art, such as mixing the varioussulfur-vulcanizable constituent rubbers with various commonly usedadditive materials such as, for example, curing aids, such as sulfur,activators, retarders and accelerators, processing additives, such asrubber processing oils, resins including tackifying resins, silicas, andplasticizers, fillers, pigments, stearic acid or other materials such astall oil resins, zinc oxide, waxes, antioxidants and antiozonants,peptizing agents and reinforcing materials such as, for example, carbonblack. As known to those skilled in the art, depending on the intendeduse of the sulfur vulcanizable and sulfur vulcanized materials(rubbers), the certain additives mentioned above are selected andcommonly used in conventional amounts.

[0096] Typical additions of carbon black comprise about 30 to about 100parts by weight, of diene rubber (phr), although about 40 to about amaximum of about 70 phr of carbon black is desirable for the highstiffness rubbers desired for the indicated fillers and plycoat(s) usedin this invention. Typical amounts of resins, if used, includingtackifier resins and stiffness resins, if used, including unreactivephenol formaldehyde tackifying resins and, also stiffener resins ofreactive phenol formaldehyde resins and resorcinol or resorcinol andhexamethylene tetramine may collectively comprise about 1 to 10 phr,with a minimum tackifier resin, if used, being 1 phr and a minimumstiffener resin, if used, being 3 phr. Such resins may sometimes bereferred to as phenol formaldehyde type resins. Typical amounts ofprocessing aids comprise about 4 to about 10.0 phr. Typical amounts ofsilica, if used, comprise about 5 to about 50, although 5 to about 15phr is desirable and amounts of silica coupling agent, if used, compriseabout 0.05 to about 0.25 parts per part of silica, by weight.Representative silicas may be, for example, hydrated amorphous silicas.A representative coupling agent may be, for example, a bifunctionalsulfur containing organo silane such as, for example,bis-(3-triethoxy-silylpropyl) tetrasulfide,bis-(3-trimethoxy-silylpropyl) tetrasulfide andbis-(3-trimethoxy-silylpropyl) tetrasulfide grafted silica from DeGussa,AG. Typical amounts of antioxidants comprise 1 to about 5 phr.Representative antioxidants may be, for example,diphenyl-p-phenylenediamine and others, such as those disclosed in TheVanderbilt Rubber Handbook (1978), pages 344-346. Suitableantiozonant(s) and waxes, particularly microcrystalline waxes, may be ofthe type shown in The Vanderbilt Rubber Handbook (1978), pages 346-347.Typical amounts of antiozonants comprise 1 to about 5 phr. Typicalamounts of stearic acid and/or tall oil fatty acid may comprise about 1to about 3 phr. Typical amounts of zinc oxide comprise about 2 up toabout 8 or 10 phr. Typical amounts of waxes comprise 1 to about 5 phr.Typical amounts of peptizers comprise 0.1 to about 1 phr. The presenceand relative amounts of the above additives are not an aspect of thepresent invention, so long as the hardness and modulus valuerequirements of the filler(s) used in the tire sidewalls in the practiceof this invention.

[0097] The vulcanization of the rubber composition(s) is/are conductedin the presence of a sulfur vulcanizing agent. Examples of suitablesulfur vulcanizing agents include elemental sulfur (free sulfur) orsulfur donating vulcanizing agents, for example, an amine disulfide,polymeric polysulfide or sulfur olefin adducts. Preferably, the sulfurvulcanizing agent is elemental sulfur. As known to those skilled in theart, sulfur vulcanizing agents are used in an amount ranging from about0.5 to about 8 phr with a range of from 3 to about 5 being preferred forthe stiff rubbers desired for use in this invention.

[0098] Accelerators are used to control the time and/or temperaturerequired for vulcanization and to improve the properties of thevulcanizate. In one embodiment, a single accelerator system may be used,i.e., primary accelerator. Conventionally, a primary accelerator is usedin amounts ranging from about 0.5 to about 3 phr. In another embodiment,combinations of two or more accelerators in which a primary acceleratoris generally used in the larger amount (0.5 to about 2 phr), and asecondary accelerator which is generally used in smaller amounts(0.05-0.50 phr) in order to activate and to improve the properties ofthe vulcanizate. Combinations of such accelerators have historicallybeen known to produce a synergistic effect of the final properties ofsulfur cured rubbers and are often somewhat better than those producedby use of either accelerator alone. In addition, delayed actionaccelerators may be used which are less affected by normal processingtemperatures but produce satisfactory cures at ordinary vulcanizationtemperatures. Representative examples of accelerators include amines,disulfides, guanidines, thioureas, thiazoles, thiurams, sulfenamides,dithiocarbamates and xanthates. Preferably, the primary accelerator is asulfenamide. If a second accelerator is used, the secondary acceleratoris preferably a guanidine, dithiocarbamate or thiuram compound, althougha second sulfenamide accelerator may be used. In the practice of thisinvention, one and sometimes two or more accelerators are preferred forthe high stiffness rubbers.

[0099] The tire can be built, shaped, molded and cured by variousmethods which will be readily apparent to those having skill in the art.

EXAMPLE I

[0100] Pre-treated carbon black and pre-treated silica reinforcingfillers are prepared by pre-treating the fillers with3,3′-dithiodipropionic acid.

[0101] The fillers were individually pre-treated by first dissolving thedithiodipropionic acid in acetone (20 ml/g) under reflux conditions. Thesolution was cooled slightly and mixed with a stirred suspension of theselected particulate filler in acetone. The pre-treated filler wasrecovered by removing the acetone via a Roto-vac instrument whichutilizes a combination of heat and vacuum to remove the acetone solventwhile rotating the mixture in a flask.

[0102] The following Table 1 summarizes the pre-treated filler showingthe amounts of dithiodipropionic acid per 100 parts of filler.

[0103] Fillers M and N are carbon black pre-treated with3,3′-dithiodipropionic acid. Fillers X and Y are silica pre-treated with3,3′-dithiodipropionic acid. TABLE 1 Pre-Treated Fillers Parts by WeightMaterial Filler M Filler N Filler X Filler Y Carbon Black¹ 100  100  0 0Silica² 0 0 100  100  DTDP³ 4 8 4 8

EXAMPLE II

[0104] Rubber compositions were prepared using the pre-treated fillersof Example I, namely the carbon black and silica reinforcing fillerswhich had been pre-treated with dithiodipropionic acid. Formulations forthe rubber compositions are shown in Table 2.

[0105] The Control rubber composition Sample A contained both carbonblack and silica reinforcing fillers which had not been pre-treated withdithiodipropionic acid.

[0106] Sample B is identical to the control with the exception of thein-situ addition of 2 phr dithiodipropionic acid during the Banburymixing step. In other words, for Sample B while 3,3′-dithiodipropionicacid is used, the carbon black and silica were not pre-treated with suchmaterial.

[0107] Samples C, D and E contain dithiodipropionic acid pre-treatedcarbon black and/or silica Samples M, N, X and Y of Example 1.

[0108] Thus, rubber compositions B, C, D and E contain 2 phrdithiodipropionic which was added (1) individually during the rubbercomposition mixing step (Sample B) or (2) as pre-treated filler duringthe rubber composition mixing step (Samples C, D and E).

[0109] Samples A-E all contain silica coupling agent added during thenon-productive stage of mixing.

[0110] Rubber compositions represented by samples F and G compare thein-situ addition of the dithiodipropionic acid (Sample F) with theaddition of pre-treated carbon black and pre-treated silica (Sample G),all in the absence of coupling agent.

[0111] For this Example, the rubber compositions were prepared by firstblending the rubber and ingredients, except for the sulfur curatives andaccelerators in a non-productive mixing stage in an internal rubbermixer to a temperature of about 160° C. for about 4 minutes.

[0112] To the rubber composition was then mixed the sulfur andaccelerators in a final productive mix stage in an internal rubber mixerto a temperature of about 105° C. for about 2 minutes.

[0113] The terms “non-productive” and “final productive” mixing stagesare well known to those having skill in the rubber mixing art. TABLE 2Silica and GB Filled Compounds Sample # A B C D E F G Pretreated/In-situPretreated Pretreated Pretreated Pretreated Control In-situ Silica CBSilica/CB In-Situ Silica/CB Non-Productive Polyisoprene¹ 100 100 100 100100 100 100 Carbon Black² 25 25 25 0 0 25 0 Silica³ 25 25 0 25 0 25 0Oil⁴ 5 5 5 5 5 5 5 Zinc Oxide 5 5 5 5 5 5 5 Stearic Acid 2 2 2 2 2 2 2Coupler⁵ 5 5 5 5 5 0 0 Filler M (CB) 0 0 0 0 26 0 26 Filler N (CE) 0 0 027 0 0 0 Filler X (Silica) 0 0 0 0 26 0 26 Filler Y (Silica) 0 0 27 0 00 0 DTDP 0 2 0 0 0 2 0 Productive Accelerators 2.5 2.5 2.5 2.5 2.5 2.52.5 Sulfur 1.5 1.5 1.5 1.5 1.5 1.5 1.5

[0114] Conventional amounts of rubber processing oil (five parts),stearic acid (two parts) and zinc oxide (5 parts), therefore, were usedwith two accelerators.

[0115] 1. Cis 1,4-polyisoprene NATSYNR 2200 from The Goodyear Tire &Rubber Company.

[0116] 2. N299 carbon black.

[0117] 3. Silica obtained as HiSil 210 from PPG.

[0118] 4. 3,3′-dithiodipropionic acid.

[0119] 5. A 50/50 composition of bis-3-(triethoxysilylpropyl)tetrasulfide carbon black obtainable as X50S from Degussa AG.

[0120] The rubber compositions of Table 2 were cured at a temperature ofabout 150° C. for about 36 minutes.

[0121] Cure behavior and cured physical properties for the rubbercompositions are shown in Table 3. TABLE 3 Sample # A B C D E F GRheometer Max Torque 49 52 52.8 52.7 51.2 46 48.2 Min Torque 5 4.8 5.35.5 6.2 5.3 7.7 delta Torque 44 47.2 47.5 47.2 45 40.7 40.5 T₉₀ 15.226.7 22.8 23.8 19 19.3 16.7 T₂ 5.1 6.9 5.3 5.7 5.9 9.3 7.4 Physicals100% Mod, MPa 3.6 4.2 4.1 4.2 4.0 2.9 3 300% Mod, MPa 16.2 16.3 13.117.1 16.9 11.2 11.5 Tensile, MPa 22.0 21.3 19.2 20.2 20.1 19.5 21.1Elongation % 422 414 368 381 381 477 502 Hardness 23° C. 69.0 73.5 75.474.4 74.3 69.5 71.6 100° C. 66.7 70.5 70.5 70.0 69.5 65.7 67.4 E′, MPa1.9 2.52 2.64 2.57 2.15 1.99 2.15 Tan.delta 60° C. 0.050 0.051 0.0480.045 0.048 0.048 0.050 Rebound, % 23° C. 57.6 56.5 56.8 57.9 57.5 59.657.8 100° C. 71.8 64.9 65.4 66.1 66.2 68.3 66.6

[0122] As shown in Table 3, the addition of the 2 phr ofdithiodipropionic acid by in-situ or by pre-treated reinforcing fillerresulted in an increased stiffness as evidenced by the rubbercompositions 100% modulus, hardness and Rheovibron E′ properties.

[0123] Further, samples F and G illustrate comparative physicalproperties for in-situ verses pre-addition in the absence of silicacoupling agent. Thus, the stiffness related physical properties weresimilar.

EXAMPLE III

[0124] Rubber compositions were prepared containing silica fillerreinforcement as shown in Table 4. They were prepared in a mannersimilar to Example II. Sample H is the Control without thedithiodipropionic acid whereas Sample I contains the pre-treated silicaof Example I and Sample J contains an in-situ addition of thedithiodipropionic acid. TABLE 4 All Silica Filled Compounds Compound #Control H Pre-mix (I) In Situ (J) Non-Productive Polyisoprene¹ 100 100100 Treated Silica² 0 52 0 Silica³ 50 0 50 Oil⁴ 5 5 5 Zinc Oxide 5 5 5Stearic Acid 2 2 2 Coupler⁵ 10 10 10 DTDP⁶ 0 0 2 ProductiveAccelerators⁷ 2.5 2.5 2.5 Sulfur 1.5 1.5 1.5

[0125] The rubber compositions of Table 4 were cured for about 36minutes at about 150° C. Cure behavior and cured properties are shown inTable 5. TABLE 5 Sample # H Pre-mix (I) In-Situ (J) Rheometer Max Torque48 56.9 56.5 Min Torque 6.9 8.2 7.4 delta Torque 41.1 48.7 49.1 T₉₀ 17.524.4 29.9 T₂ 7 8.3 9.5 Physicals 100% Mod, MPa 3.1 4.3 4.0 300% Mod, MPa12.9 16.1 15.0 Tensile, MPa 21.9 21.4 21.5 Elongation % 491 419 443Hardness  23° 69.5 76.6 75.7 100° C. 67.6 72.9 71.7 E′, MPa 1.60 2.562.75 Tan D 60° C. 0.051 0.035 0.034 Rebound, %  23° 56.9 58.9 57.1 100°C. 71.3 66.9 65.2

[0126] Inspection of the physical properties shown in Table 5 clearlyindicates that the experimental samples I and J which containdithiodipropionic acid exhibit higher stiffening properties such as 100percent modulus, hardness and E′ than the Control H sample.

EXAMPLE IV

[0127] Rubber compositions were prepared in which 3,3′-dithiodipropionicacid and benzoic acid are blended in-situ with a carbon black reinforcedrubber composition.

[0128] For the experimental (K) rubber composition dithiodipropionicacid was added in-situ in the non-productive mix stage.

[0129] For the experimental (L) rubber composition benzoic acid wasadded in the productive mix stage.

[0130] The rubber compositions were prepared and mixed by conventionalrubber mixing processes and comprised of the materials shown in Table 6.

[0131] The rubber compositions were mixed by first blending the rubberand ingredients, except for the sulfur curatives and accelerators in annonproductive mixing stage in an internal rubber mixer to a temperatureof about 160° C. for about 4 minutes.

[0132] Sulfur and accelerators were then added in a final productive mixstage in an internal rubber mixer to a temperature of about 105° C. forabout 2 minutes. TABLE 6 Sample # K L 1^(st) Non-Productive NaturalRubber 80 80 Cis 1,4-Polybutadiene¹ 20 20 Carbon Black 60 60 ProcessingOil 4 4 Antidegradants² 1.8 1.8 Zinc Oxide 6 6 Fatty Acid 1 1Dithiodipropionic Acid 1.5 0 2^(nd) Non-Productive Silica³ 5 5 Bis-(3- 11 triethoxysilylpropyl tetrasulfide (50% active) Productive Benzoic Acid0 1.5 Sulfur 3.2 3.2 Accelerators⁴ 2.5 2.5 Zinc Oxide 2 2

[0133] The rubber compositions were cured for about 36 minutes to atemperature of about 150° C.

[0134] The physical properties are shown in Table 7. TABLE 7 Sample # KL Rheometer (150° C.) Max. Torque, dNm 56.0 56.9 Min. Torque 6.0 6.4Delta Torque 50.0 50.5 T₉₀, minutes 12.9 9.8 Stress-Strain TensileStrength, MPa 16.2 15.2 Elongation @ Break, % 249 228 100% Modulus, MPa5.9 6.3 Rebound 100° C. 64.8 62.0 Hardness Shore A, 100° C. 72 73

[0135] The cured physical properties show that the addition ofdithiodipropionic acid or benzoic acid to the rubber compositionresulted in a rubber composition having a relatively high hardness valueof about 72.

EXAMPLE V

[0136] Rubber compositions were prepared in which salicylic acid wasblended with a carbon black reinforced natural rubber composition.

[0137] The formulation (M) was a control without salicylic acid beingadded.

[0138] For the experimental (N) rubber composition salicylic acid wasadded in the non-productive mix stage.

[0139] The rubber compositions were prepared and mixed by conventionalrubber mixing processes and comprised of the materials shown in Table 8.

[0140] The rubber compositions were mixed by first blending the rubberand ingredients, except for the sulfur curatives and accelerators in annonproductive mixing stage in an internal rubber mixer to a temperatureof about 160° C. for about 4 minutes.

[0141] Sulfur and accelerators were then added in a final productive mixstage in an internal rubber mixer to a temperature of about 105° C. forabout 2 minutes. TABLE 8 Sample # M (Ctrl) N Non-Productive NaturalRubber¹ 100 100 Carbon Black, N299 50 50 Processing Oil 5 5Antidegradants² 2 2 Zinc Oxide 5 5 Fatty Acid 2 2 Salicylic Acid 0 2Productive Sulfur 1.4 1.4 Accelerators³ 1 1

[0142] The rubber compositions were cured for about 36 minutes to atemperature of about 150° C.

[0143] The physical properties are shown in Table 9. TABLE 9 Sample # M(Ctrl) N Rheometer (150° C.) Max. Torque, dNm 37.7 40.2 Min. Torque, dNm6.2 6.2 Delta Torque 31.5 34.0 T₉₀, minutes 18.8 24.5 Stress-StrainTensile Strength, MPa 21.3 23.1 Elongation @ Break, % 539 468 100%Modulus, MPa 1.58 2.89 Rebound 100° C. 61.1 59.5 Hardness Shore A, 100°C. 48.0 65.2

[0144] The cured physical properties show that the addition of salicylicacid to the rubber composition resulted in a rubber composition havingrelatively high modulus and hardness values.

[0145] In the practice of this invention, it is considered importantthat the rubber compositions for one or more of the inserts arerelatively very stiff, moderately hard, and have a low hysteresis.

[0146] It is important to appreciate that the indicated physicalproperties of the rubber compositions in Table 5 and 7 are for samplesthereof and that the dimensions, including thickness, of the resultingtire components (inserts and plies) need be taken into account asfactors contributing to the overall stiffness and dimensional stabilityof the tire sidewall and carcass.

[0147] The hysteresis or Tan Delta values for the rubber composition forthe aforesaid fillers is desirably somewhat lower than that for therubber composition for the aforesaid ply coat(s) because of the bulk ofthe inserts versus the thin dimensions of the plycoat.

[0148] In the practice of this invention, it is considered importantthat the rubber compositions for one or more of the inserts 12 arerelatively very stiff, moderately hard, and have a low hysteresis.

[0149] Chafing of the tire in the lower bead region radially outward ofthe carcass structure adjacent the rim flange may be minimized,especially during use of the tire in the uninflated condition, byproviding hard rubber chafer portion 7.

[0150] In one embodiment of the invention, a fabric overlay having cordsat about zero degrees in relation to the centerplane of the tire isplaced over the belt reinforcing structure 9.

[0151] While certain representative embodiments and details have beenshown for the purpose of illustrating the invention, it will be apparentto those skilled in this art that various changes and modifications maybe made therein without departing from the spirit or scope of theinvention.

What is claimed is:
 1. A tire comprised of a toroidally-shaped carcassand an outer, circumferential tread designed to be ground contacting,wherein said carcass is comprised of two spaced apart inextensible beadportions, two spaced apart sidewalls each individually extendingradially inward from and connecting said tread to said bead portions,and at least one cord reinforced ply extending from bead to bead andthrough the sidewalls; an improvement in which a substantially crescentshaped rubber insert is juxtapositioned to and axially inward of atleast one of said carcass plies in each of said sidewalls or the tire;wherein the rubber composition of said insert has a Shore A hardness at100° C. in a range of about 65 to about 85, a 100 percent Modulus in arange of about 3.5 to about 10, a Hot Rebound at 100° C. in a range ofabout 60 to about 80, an E′ value in a range of about 2 to about 20 MPaat 60 C and a Tan.Delta value at 60 C in a range of about 0.03 to about0.15; and wherein said rubber composition of said insert is comprisedof, based on 100 parts by weight rubber, (A) at least one diene-basedelastomer, (B) about 30 to about 100 phr of particulate reinforcement ascarbon black and, optionally, silica, and (C) about 0.5 to about 10 phrof a material selected from at least one of dithiodipropionic acid,benzoic acid and salicylic acid.
 2. The tire of claim 1 wherein saidcarbon black and/or silica filler is pre-treated with at least one ofsaid acids to form a composite thereof and said composite is firstblended with ingredients for said rubber composition in the absence offree sulfur and of vulcanization accelerators and free sulfur andvulcanization accelerators subsequently mixed with the rubbercomposition; wherein said acid(s) is adsorbed, absorbed, coated ormelt-sprayed onto the surface of said filler.
 3. The tire of claim 1wherein said acid is blended in-situ with ingredients for said rubbercomposition in the absence of free sulfur and vulcanization acceleratorsand free sulfur and vulcanization accelerators subsequently mixed withthe rubber composition.
 4. The tire of claim 1 wherein said acid is3,3′-dithiodipropionic acid.
 5. The tire of claim 2 wherein said acid is3,3′-dithiodipropionic acid.
 6. The tire of claim 3 wherein said acid is3,3′-dithiodipropionic acid.
 7. The tire of claim 1 wherein said insertis substantially in an entrunkated crescent shape, where the entrunkatedportion thereof is juxtapositioned to the said tire bead portion.
 8. Thetire of claim 2 wherein said insert is substantially in an entrunkatedcrescent shape, where the entrunkated portion thereof is juxtapositionedto the said tire bead portion.
 9. The tire of claim 3 wherein saidinsert is substantially in an entrunkated crescent shape, where theentrunkated portion thereof is juxtapositioned to the said tire beadportion.
 10. The tire of claim 4 wherein said insert is substantially inan entrunkated crescent shape, where the entrunkated portion thereof isjuxtapositioned to the said tire bead portion.
 11. The tire of claim 1wherein said tire carcass has from two to three plies comprised of afirst axially inner ply and one or two additional plies as a second plyand third ply, respectively, each additional ply positioned sequentiallyaxially outward from said first ply.
 12. The tire of claim 1 whereinsaid tire carcass contains one ply wherein said insert isjuxtapositioned to and axially inward of said ply in the sidewall regionof the tire and where said ply is wrapped around the bead portion with aturn-up portion of the ply extending into the sidewall region andaxially outward of the first ply.
 13. The tire of claim 1 wherein saidtire carcass contains an axially inner first ply and an axially outersecond ply; wherein said insert is juxtapositioned to and axially inwardof said first ply, in the sidewall region of the tire.
 14. The tire ofclaim 13 wherein said second ply extends substantially from bead to beadthrough the sidewalls without connecting with the bead portion.
 15. Thetire of claim 1 wherein said carcass contains an axially inner first plyand an axially outer second ply; wherein said insert is juxtapositionedto and interposed between said first and second ply, in the sidewallregion of the tire.
 16. The tire of claim 15 wherein said second plyextends substantially from bead to bead through the sidewalls withoutconnecting with the bead portion.
 17. The tire of claim 15 whereinanother of said inserts is juxtapositioned to and axially inward of saidfirst ply, in the sidewall region of the tire.
 18. The tire of claim 17wherein said second ply extends substantially from bead to bead throughthe sidewalls without connecting with the bead portion.
 19. The tire ofclaim 16 wherein the carcass contains an axially inner first ply, asecond ply axially outward from said first ply and a third ply axiallyoutward from said second ply; wherein said insert is juxtapositioned toand axially inward of said first ply, in the sidewall region of thetire.
 20. The tire of claim 1 wherein the carcass contains an axiallyinner first ply, a second ply axially outward from said first ply and athird ply axially outward from said second ply; wherein said insert isjuxtapositioned to and interposed between said first and second plies,in the sidewall region of the tire.
 21. The tire of claim 1 wherein thecarcass contains an axially inner first ply, a second ply axiallyoutward from said first ply and a third ply axially outward from saidsecond ply; wherein said insert is juxtapositioned to and interposedbetween said second and third plies, in the sidewall region of the tire.22. The tire of claim 20 wherein at least one of said second and thirdplies extends substantially from bead to bead through the sidewallswithout connecting with the bead portion.
 23. The tire of claim 21wherein at least one of said second and third plies extendssubstantially from bead to bead through the sidewalls without connectingwith the bead portion.
 24. The tire of claim 20 wherein an additionalinsert is juxtapositioned to and axially inward of said first ply in thesidewall region of the tire.
 25. The tire of claim 21 wherein anadditional insert is juxtapositioned to and axially inward of said firstply in the sidewall region of the tire.
 26. The tire of claim 22 whereinan additional insert is juxtapositioned to and axially inward of saidfirst ply in the sidewall region of the tire.
 27. The tire of claim 23wherein an additional insert is juxtapositioned to and axially inward ofsaid first ply in the sidewall region of the tire.
 28. The tire of claim1 wherein said innermost insert has a Shore A hardness in a range ofabout 65 to about 75, a 100 percent modulus in a range of about 3.5 toabout 8 MPa, and E′ in a range of about 2 to about 15 MPa at 60° C. anda Tan.Delta at 60° C. in a range of about 0.03 to about 0.1 and saidoutward insert(s) has Shore A hardness in a range of about 70 to about85, a 100 percent modulus in a range of about 5 to about 10 MPa, and E′in a range of about 5 to about 20 MPa at 60° C. and a Tan.Delta at 60°C. in a range of about 0.05 to about 0.15.
 29. The tire of claim 1 wherethe cords of said innermost ply are of steel, carbon fiber or fiberglassand the cords of said outer ply(ies) are of nylon or rayon.
 30. The tireof claim 2 where the cords of said innermost ply are brass and/or zinccoated steel and the cords of said outer ply(ies) are of nylon or rayon.31. The tire of claim 1 , wherein said material (C) is3,3′-dithiodipropionic acid; wherein said carcass contains at least twoplies with an insert juxtapositioned to and interposed between each ofthe plies and an additional insert juxtapositioned to and axially inwardof the innermost ply; wherein the cords for the innermost ply are ofbrass and/or zinc plated steel and the cords for the outermost ply(plies) are of nylon or rayon; and wherein said insert(s) have a maximumthickness about midway between the bead portions and tread in thesidewall region of the tire.
 32. The tire of claim 1 wherein saidinnermost insert has a Shore A hardness in a range of about 65 to about75, a 100 percent modulus in a range of about 3.5 to about 8 MPa, and E′in a range of about 2 to about 15 MPa at 60° C. and a Tan.Delta at 60°C. in a range of about 0.03 to about 0.1 and said outward insert(s) hasShore A hardness in a range of about 70 to about 85, a 100 percentmodulus in a range of about 5 to about 10 MPa, and E′ in a range ofabout 5 to about 20 MPa at 60° C. and a Tan.Delta at 60° C. in a rangeof about 0.05 to about 0.15.
 33. The tire of claim 31 wherein saidinsert is substantially in an entrunkated crescent shape, where theentrunkated portion thereof is juxtapositioned to the said tire beadportion.